Pfizer-BioNTech Testing 3 Doses to Boost Vaccine Efficacy in Children Under 5

Pfizer-BioNTech will be testing 3 doses of their vaccine in children older than 6 months and younger than 5 years, instead of the original 2-dose regimen.

Today, Pfizer-BioNTech announced it would be testing 3 doses of its COVID-19 vaccine in infants and children older than 6 months and younger than 5.

A typical regimen of the Pfizer-BioNTech COVID-19 vaccine includes 2 doses, with a third “booster” dose recommended at least 6 months later for all Americans 16 years and older.

Upon reviewal of preliminary analysis suggesting 2-4-year-olds did not have an adequate response to 2 doses of the vaccine, Pfizer-BioNTech decided to administer an additional dose in their study. In a joint statement, the companies said immunogenicity was reached in the 6-24-month-old population, but not the 2-under 5-year-old population.

The US Food and Drug Administration (FDA) and European Medicines Agency approved the change, allowing Pfizer-BioNTech to administer an additional dose in their study of children 6 months-under 5 years.

Each vaccine dose for children under 5 will be 3 mg, or a tenth of what adults receive. Children 5-11 years of age currently receive a third of the adult dose.

Pfizer-BioNTech was expected to release data from its study of children under 5 by the end of 2021. If the 3-dose study is successful, they plan to apply for Emergency Use Authorization (EUA) to administer vaccines to this age group by the first half of 2022.

At this time, Pfizer-BioNTech have not reported any safety concerns in their study of vaccinating children under 5.

Pfizer-BioNTech are also planning to evaluate a third booster dose of their 10 mg vaccine in children 5-12 years old. Currently underway is a study of 10 or 30 mg booster doses in adolescents 12-17 years of age.

Pfizer-BioNTech announced, “These updates were informed by the effectiveness data for three doses of the vaccine for people 16 years and older, and the early laboratory data observed with Delta and other variants of concern, including Omicron, which suggest that people vaccinated with three doses of a COVID- 19 vaccine may have a higher degree of protection.”